[Grace Themes]

Hi,

The slider works fine with no issue in all of our demo site and various clients website.

If you don’t want to use this default image slider, you can use any image slider WordPress plugin

Go to Appearance » Theme Options » Homepage Slider
Enter your slider shortcode which is provided by plugin without php tag

Please check the documentation
https://www.gracethemes.com/documentation/milestone-doc/#homepage-slider

Regards
Grace Themes